Methods and instrumentation for inserting intervertebral grafts and devices

ABSTRACT

Instruments for inserting an implant in a space between adjacent bony portions include upper and lower guide members separated by a spreader with the implant positioned forwardly of the spreader. The spreader is movable forwardly between the guide members with a drive member to position the implant in a space between the bony portions. The spreader contacts the adjacent bony portions to facilitate withdrawal of the inserter instrument when the implant is positioned in the space.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 10/764,621 filed on Jan. 26, 2004, which is incorporated hereinby reference in its entirety.

BACKGROUND

The repair and reconstruction of bony structures is sometimesaccomplished by directly fixing adjacent bony portions to each other,such as by a plate. In other instances, bone growth inducing materialcan be introduced between the adjacent bony portions, which over timeresults in a solid bony connection. In some instances, the adjacent bonyportions are not sufficiently strong to maintain their patency as thebone heals or the bone grows between the adjacent structures through thebone growth inducing material. In these instances, grafts, cages,artificial joints and other implants have been provided to engage theadjacent bony structures to provide additional stability.

One problem, among others, with such implants is associated withpositioning the implant in the space between adjacent bony portions.Insertion can be difficult or time consuming if the bony portions arespaced too close together, or if the adjacent tissue, nerves orvasculature impedes access to or placement of the implant in the spacebetween the bony portions. Furthermore, maintenance of distraction ofthe space during insertion of the implant requires additionalinstruments in the space or in the operative approach to the space whichcan make the procedure more invasive and impede access and visibilityduring implant insertion.

SUMMARY

The invention provides instruments that facilitate placement of animplant between adjacent bony portions.

According to one aspect, the instrument includes a housing and a pair ofopposing guide members coupled to the housing. The guide members eachinclude an elongated slot opening between an outer surface and a guidesurface of the guide member. A spreader is positioned between the pairof guide members. The spreader includes a central body and a pair ofopposite wings extending therefrom slidingly received in the slot of acorresponding one of the pair of guide members. A drive member iscoupled to the spreader and operable to forwardly advance the spreaderand the implant positioned forwardly of the spreader toward distal endsof the guide members.

According to another aspect, the instrument includes a housing and apair of opposing guide members coupled to the housing. A spreader ispositioned between the pair of guide members. An adapter is releasablycoupled to the spreader with a body portion of the adapter along aforward or distal end wall of the spreader. A drive member is coupled tothe spreader and is operable to forwardly advance the spreader andadapter with the implant positioned forwardly of the adapter towarddistal ends of the guide members. The adapter positions the implant moreforwardly relative to the guide members than if the implant werepositioned along the forward or distal end wall of the spreader.

In a further aspect, a method for inserting an implant in a spacebetween adjacent bony structures includes: providing an implant inserterwith a pair of guide members pivotally coupled to a housing and aspreader between the pair of guide members; pivoting at least one of thepair of guide members away from the other of the pair of guide membersto remove a wing of the spreader from a slot of the at least one guidemember; positioning an implant between the pair of guide members andforwardly of the spreader; and pivoting the at least one guide membertoward the other guide member thereby positioning the wing of thespreader in the slot of the at least one guide member.

In a further aspect, the method includes withdrawing distal supportmembers of the pair of guide members from the space between the implantand the adjacent bony portions by manipulating the drive member to pushthe wings against the adjacent bony portions and proximally displacingthe guide members relative to the bony portions and the implant.

These and other aspects can be discerned from the following writtendescription and accompanying figures.

DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of an implant inserter instrument.

FIG. 2 is a perspective view of a housing of the inserter instrument ofFIG. 1.

FIG. 3 is a perspective view of the housing of FIG. 2 coupled with adrive member.

FIG. 4 is a perspective view of the housing and drive member assembledwith a spreader coupled to a distal end of the drive member and anoptional adapter exploded from the spreader.

FIG. 5 is a front elevational view of the spreader.

FIG. 6 is a perspective view of the adapter.

FIG. 7 is a perspective view of the housing, drive member, and spreaderassembled with a lower guide member.

FIG. 8 is a perspective view of the housing, drive member, spreader andlower guide member assembled with an implant holder.

FIG. 9 is a perspective view of the assembly of FIG. 8 with an implantpositioned forwardly of the spreader on the lower guide member.

FIG. 10 is a perspective view of a distractor assembly with a distractorhead thereof positioned in a spinal disc space.

FIG. 11 is a perspective view of a shaft assembly comprising a portionof the distractor assembly of FIG. 10.

FIG. 12 is a perspective view of a rasp assembly with a rasp head in thespinal disc space and coupled to a distal end of the shaft assembly ofFIG. 11.

FIG. 13 is a perspective view of a mallet.

FIG. 14 is a perspective view of implant inserter instrument with animplant being loaded therein.

FIG. 15 is a perspective view of the loaded implant inserter instrumentpositioned for delivery of an implant to the spinal disc space.

FIG. 16 is a perspective view of the loaded implant inserter instrumentwith the implant driven distally toward the spinal disc space.

FIG. 17 is a perspective view of the loaded implant inserter instrumentwith the implant driven into the spinal disc space and the spreadercontacting the adjacent vertebral bodies.

FIG. 18 is a perspective view of the implant inserter instrument withthe implant unloaded into the spinal disc space and the spreaderadvanced to the distal end of the guide member slots to withdraw theguide members from the spinal disc space.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

For the purpose of promoting an understanding of the principles of theinvention, reference will now be made to the illustrated embodimentsthereof and specific language will be used to describe the same. It willnevertheless be understood that no limitation of the scope of theinvention is thereby intended. Any such alterations and furthermodifications in the invention, and any such further applications of theprinciples of the invention as described herein are contemplated aswould normally occur to one skilled in the art to which the inventionrelates.

An instrument is provided for inserting implants and other devices intoa space between adjacent bony portions to support the adjacent bonyportions. The inserter instrument can be used with any type of bonesupport implant, such as artificial joints, spacer devices, and fusiondevices, for example. The implants can be made from bone material or anysuitable biocompatible metal, plastic, or other material. In oneapplication, the inserter instrument is employed in spinal surgicalprocedures for inserting an implant in the disc space between adjacentvertebrae. For example, in the illustrated embodiments of FIGS. 10, 12and 15-18, the adjacent bony portions include first vertebra 220 andsecond vertebra 222. The vertebrae 220, 222 include a disc space 224therebetween, which provides a space for insertion of an implant betweenthe adjacent bony portions. The inserter instrument can also be used incorpectomy procedures to position an implant between adjacent vertebraeon either side of one or more removed or partially removed vertebralbodies. The inserter instrument can be used in various approaches to thespine, including posterior, posterior lateral, transforaminal, lateral,anterior lateral, oblique, and anterior approaches. The inserter canalso be used in approaches to various regions of the spine, includingthe lumbar, thoracic and cervical regions. It is contemplated that theinserter instrument can have application in surgical procedures otherthan spinal surgical procedures to facilitate insertion of an implantbetween adjacent bony portions.

In FIG. 1 an inserter instrument 20 is shown. Inserter instrument 20includes an intermediate housing 22 with a drive member 40 extendingthrough and coupled thereto. Drive member 40 includes an implant holder140 extending therethrough. A pair of guide members 100, 120 are coupledto housing 22 and extend distally therefrom. The distal ends of drivemember 40 and implant holder 140 extend in the space between guidemembers 100, 120. The distal end of drive member 40 engages a spreader60 positioned between guide members 100, 120. An implant 160 ispositioned forwardly of spreader 60. Implant holder 140 extends throughspreader 60 and engages implant 160 to facilitate in maintaining itspositioning between guide members 100, 120. Spreader 60 is moveabledistally or forwardly by manipulating drive member 40 relative tohousing 22 to advance drive member 40 forwardly towards distal ends ofguide members 100, 120.

The proximal ends of guide members 100, 120 are pivotally attached tohousing 22, facilitating loading of the implant 160 and placement of thedistal ends of guide members 100, 120 adjacent one another forpositioning in the spinal disc space. As spreader 60 pushes implant 160distally between guide members 100, 120, the distal ends of guidemembers 100, 120 can separate and thus apply a distraction force to theadjacent vertebrae. The vertebrae are distracted sufficiently to receiveimplant 160 since the final distraction height is determined by theheight of implant 160 between the distal ends of guide members 100, 120.

Further details of the assembly of inserter instrument 20 will bediscussed with further reference to FIGS. 2-9. In FIG. 2 there is shownhousing 22. Housing 22 includes a drive member engaging portion 24extending proximally from a distal coupling portion 26. A passage 38extends through each of drive member engaging portion 24 and couplingportion 26. Coupling portion 26 includes a pair of upwardly andproximally extending upper fingers 28, 32 projecting therefrom. Fingers28, 32 form proximally opening receptacles 30, 34, respectively, whichreceive and pivotally capture a guide member 120 (FIG. 14) to couplingportion 26. A slot 36 extends between fingers 28, 32 and along thedistally oriented face of coupling member 26 between a pair of oppositelower fingers, only one of which, finger 38, is shown. The lower fingersare identical to upper fingers 28, 32, and pivotally capture lower guidemember 100 to coupling member 26.

It should be understood that the terms “upper” and “lower” refer to theorientation of the elements of the instruments in the Figures as shownin an operative approach to the space between adjacent bony portions.The instruments can be rotated or repositioned such that, for example,the lower fingers extend upwardly and guide member 100 is positionedabove guide member 120.

Referring to FIG. 3, drive member 40 is coupled to housing 22. In theillustrated embodiment, drive member 40 includes a shaft 42 and proximalhandle 46. Handle 46 includes opposite first and second arms 48, 50extending from a central body portion 47 to facilitate grasping ofhandle 46. A proximal recess 52 is provided in the central body portion47 of handle 46. Shaft 42 extends through passage 38 of housing member22 to a distal end 44. At least a portion of shaft 42 is threaded tothreadingly engage an internally threaded portion of passage 38.Accordingly, drive member 40 is movable longitudinally distally andproximally by rotating shaft 42 in housing 22, thereby distally orproximally displacing distal end 44.

In another embodiment, drive member 40 can include a ratchet mechanism.A ratchet bar can be provided along shaft 42, which is moved linearlyproximally in housing 22 to distally advance spreader 60 between guidemembers 100, 120. A handheld trigger-like handle, pinion with athumbwheel or tool engaging end, or other suitable handle can beprovided to effect the linear movement of the ratchet bar. A catchmechanism, either in the handle or housing 22, can maintain the distalpositioning of the ratchet bar until it is released, allowing theratchet bar to be linearly and proximally moved.

In FIG. 4, there is shown spreader 60 attached to distal end 44 of drivemember 40. Spreader 60 includes a central body 62 having an upper wing64 and a lower wing 66 extending therefrom in opposite directions fromone another, as shown in FIG. 5. A bore 72 extends centrally throughcentral body 62, and opens at the distal and proximal ends thereof.Distal end 44 of drive member 40 is rotatably received in the trailingor proximal end opening of bore 72. In the illustrated embodiment,distal end 44 includes a circumferential groove to receive a ballplunger in spreader 60. Other suitable rotatable coupling arrangementsare also contemplated, such as a C-ring or other suitable connector.Depending on the direction of rotation of drive member 40 about itslongitudinal axis, spreader 60 moves distally or proximally withoutrotation.

Spreader 60 further includes leading or distal end wall that is angledproximally to a central concave receptacle 76. Bore 72 opens intoreceptacle 76. Spreader 60 further includes lateral sidewalls withgrooves 68, 70 formed therein. Each of the sidewalls further includes adetent, such as detent 74 shown in groove 70. The proximally recessedleading or distal end wall of spreader 60 at least partially receivesimplant 160 positioned forwardly thereof, and resists rotation of theimplant 160 as it is advanced between guide members 100, 120.

The recessed distal end wall and grooved lateral walls of spreader 60further facilitate engagement of an optional adapter 80 to spreader 60.Adapter 80 includes a body 82 having a pair of arms 84, 86 extendingproximally therefrom. Body 82 includes a profile that matches theprofile of the leading or distal end wall of spreader 60. Body 82includes a central offset portion 88 adapted to fit within receptacle 76of spreader 60. Offset portion 88 includes a central hole 90 throughwhich the distal end of implant holder 140 extends to engage implant160, as discussed further below. Arms 84, 86 include protrusions, suchas protrusion 92 on arm 84, extending toward one another. Theprotrusions releasably engage the adjacent detent in the lateral wallsof spreader 60 when adapter 80 is positioned adjacent the leading ordistal end wall of spreader 60, engaging adapter 80 thereto.

When coupled to spreader 60, adapter 80 positions the implant moredistally relative to guide members 100, 120 by a distance 94 that atleast corresponds to the thickness of body 82 and any space between body82 and the distal end wall of spreader 60. This allows implant 160 to bepositioned more distally in the spinal disc space when spreader 60 isadvanced to the ends of guide members 100, 120. It is contemplated thatmultiple adapters 80 can be provided in a set to allow the surgeon toselect an adapter providing a desired offset distance.

Referring to FIG. 7, lower guide member 100 is pivotally coupled tocoupling portion 26 of housing 22. Upper guide member 120 can bepivotally coupled with the upper fingers 28, 32 of housing 26, as shownin FIG. 14. The proximal ends of guide members include laterallyoriented crossbars, such as crossbar 132 shown in FIG. 14. The ends ofcrossbar 132 are received in corresponding ones of the proximallyopening receptacles 30, 34, and reside against the fingers 28, 32, whichmaintain the guide member 100 in pivotal and removable engagement withhousing 26. Lower guide member 100 is similarly pivotally and removablycoupled to the opposite, downwardly extending fingers of couplingportion 26. The ability to quickly disassemble guide members 100, 120allows inserter instrument 20 to be cleaned and sterilized after thesurgical procedure is completed. It further allows guide members 100,120 to be provided in a set of guide members for use with a commonhousing, drive member and implant holder. For example, the guide membersin the set can include various lengths, widths, or abutment memberconfigurations from which the surgeon may select during surgery.

Guide members 100, 120 extend distally from housing 22, and define apath for insertion of an implant between the adjacent bony portions,such as vertebrae 220, 222. As shown in FIG. 8, guide member 100includes a body 110 extending from a proximal end 112 to a distal end106. Body 110 can be provided with an elongated guide slot 102 extendingtherethrough along a central axis of body 110. Guide slot 102 opensalong a guide surface 101 and an opposite outer surface 103 of body 110.Guide slot 102 extends from a location adjacent proximal end 112 to alocation adjacent distal end 106. Guide slot 102 includes an enlargedproximal end opening 108 for passage of the enlarged outer end of lowerwing 66. The remaining proximal portion of guide slot 102 is sized toslidingly receive the body 67 of lower wing 66, but prevents passage ofthe enlarged outer end of wing 66 therethrough.

Similarly, as shown in FIG. 14, guide member 120 includes a body 134extending from a proximal end 130 to a distal end 126. Body 134 can beprovided with an elongated guide slot 122 extending therethrough along acentral axis of body 134. Guide slot 122 opens along a guide surface 121and opposite outer surface 123 of body 134. Guide slot 122 extends froma location adjacent proximal end 130 to a location adjacent distal end126. Guide slot 122 includes an enlarged proximal end opening 128 forpassage of the enlarged outer end of upper wing 64. The remainingproximal portion of guide slot 122 is sized to slidingly receive thebody 65 of upper wing 64, but prevents passage of the enlarged outer endof wing 64 therethrough.

Guide member 100 can be provided with an abutment member 104 adjacentdistal end 106 projecting from outer surface 103 for contacting theadjacent bony structure to limit the insertion depth of guide member 100into the space between the adjacent bony portions. A support member 107of guide member 100 extends distally from abutment member 104 and intothe space between the adjacent bony portions, forming an extension ofguide surface 101 and outer surface 103. Guide member 120 can beprovided with an abutment member 124 projecting from outer surface 123adjacent distal end 126 for contacting the adjacent bony portion tolimit the insertion depth of guide member 120 into the space between theadjacent bony portions. A support member 127 extends distally fromabutment member 124 and into the space between the adjacent bonyportions, forming an extension of guide surface 121 and outer surface123.

When assembled to housing 22, the guide surfaces 101, 121 of guidemembers 100, 120 are oriented toward one another. Support members 107,127 can extend along an adjacent surface of the adjacent bony portion tofacilitate insertion of the implant 160 into the space between theadjacent bony portions. Support members 107, 127 also contact theadjacent bony portions to distribute a spreading or distraction forcethereto. The spreading or distraction force can be applied to theadjacent bony portions by separating guide members 100, 120 as theimplant 160 and spreader 60 are distally advanced between guide members100, 120. Support members 107, 127 further protect the adjacentvertebral endplate as implant 160 is positioned in the space between theadjacent bony portions. Support member 107, 127 can prevent implant 160from cutting into or becoming engaged with bony structure at theentrance into the space therebetween, and facilitate insertion ofimplant 160 in the desired position in the space between the adjacentbony portions.

Referring now to FIG. 8, implant holder 140 is shown positioned throughpassage 54 (FIG. 3) of drive member 40. Implant holder 140 includes anelongated shaft extending from a distal end 144 to an adjustment member142 at its proximal end. Adjustment member 142 is received in recess 52(FIG. 3) of handle 46, and can be grasped by the surgeon to rotate theshaft and thus distal end 144 to engage a female threaded hole inimplant 160 positioned forwardly of spreader 60, as shown in FIG. 9.Implant holder 140 firmly holds implant 160 against the leading ordistal end wall of spreader 60. Other embodiments contemplate othercoupling arrangements between distal end 144 and implant 160, includingan interference fit, snap fit, ball plunger and groove, or othersuitable releasable coupling arrangement.

One procedure employing inserter instrument 20 will be discussed withreference to FIGS. 10-18. In FIG. 10 there is shown distractor head 170coupled to a distal end of a shaft assembly 180. Distractor head 170includes a tapered leading end nose 172 to facilitate insertion intodisc space 224 between vertebrae 220, 222 when the disc space iscollapsed. The body of distractor head 170 tapers to an upper surface174 and an opposite lower surface (not shown.) The upper and lowersurfaces define a distraction height that separates the adjacentvertebral endplates to a corresponding disc space height when distractorhead 170 is inserted. Distractor head 170 further includes a proximalflange member 176 for coupling with shaft assembly 180. After insertionof distractor head 170, the disc space height is evaluated to determineif the proper disc space height has been obtained. It is contemplatedthat a number of distraction heads of various heights can be providedfor sequential distraction of disc space 224. If the last inserteddistractor head does not provide the desired disc space height, a seconddistractor head is selected and coupled to shaft assembly 180 forinsertion into the disc space. The process is repeated until the discspace height desired has been attained.

Further details of shaft assembly 180 are shown in FIG. 11. Shaftassembly 180 includes a shaft 182 extending to a distal coupling end188. Distal coupling end 188 is removably engageable to distractor head170 and, as shown in FIG. 12, a rasp head 190. In one embodiment, distalcoupling end 188 includes external threads to engage a threaded hole inflange member 176. Other embodiments contemplate other couplingarrangements, including a snap fit, a quick connect coupler, forexample. It is also contemplated that shaft assembly 180 can beintegrally formed with distractor head 170 or rasp head 190. A handle184 is provided at the proximal end of shaft 182 to facilitate insertionand withdrawal of the distractor and rasp heads. A collar 186 extendsabout shaft 182 distally of handle 184 to provide a platform to receiveimpaction forces for insertion or withdrawal of the distractor or raspheads from the disc space.

In FIG. 12 there is shown rasp head 190, which is also removablyattachable to distal coupling end 188 of shaft assembly 180 at proximalflange member 196. Rasp head 190 includes a tapered leading end nose 192and a body 194. The upper and lower surfaces of body 194 includeroughened surfaces to facilitate rasping of bone material of theadjacent vertebral endplates. Body 194 defines a height between theupper and lower surfaces that corresponds to the height of the lastdistractor head inserted into the disc space. Thus, it is contemplatedthat rasp head 190 can be provided in a set of a number of rasp headswith heights corresponding to heights of distractor heads provided inthe set.

In FIG. 13 there is shown a mallet 200, which includes a shaft 202 and aproximal handle 204. An impaction head 206 is provided at the distal endof shaft 202. Impaction head 206 includes a U-shaped recess 210 formedby distally extending arms 208 on each side thereof. Arms 208 arepositionable about shaft 182 of shaft assembly 180. Mallet 200 ispositioned proximally of collar 186 to deliver an impaction insertionforce, or distally of collar 186 to deliver an impaction removal force.

After distraction of the disc space with distractor head 170 andpreparation of the endplates with rasp head 190, implant 160 can bedelivered to the disc space with inserter instrument 20. In FIG. 14,upper guide member 120 is pivoted away from lower guide member 100 tofacilitate placement of implant 160 forwardly of spreader 60. Implantholder 140 is then rotated to engage the implant 160 and hold it inplace against the leading end wall of spreader 160. If desired, adapter80 can be mounted to spreader 60 to provide a more distal placement ofimplant 160 relative to guide members 100, 120 and spreader 60. Drivemember 140 is fully retracted or withdrawn proximally relative tohousing 22 so that spreader 60 is placed in alignment with enlarged slotportions 108, 128, allowing guide member 100 to be lowered into placeabout upper wing 64, as shown in FIG. 15.

In one embodiment, it is contemplated that implant 160 is selected froma set of implants having various heights and or angulation between itsupper and lower surfaces. The implant of the appropriate height can beselected to provide a height that corresponds to the distractor headproviding the desired disc space height during distraction. In thismanner, when the implant is inserted, it will fit within the disc spacesince an indication of its fit has already been provided by the lastinserted distractor head.

With the distraction and rasping instruments removed from disc space224, the implant 160 is loaded into inserter instrument 20. The pivotingcoupling arrangement of guide members 100, 120 allows distal ends 106,126 to be positioned adjacent one another. This provides a low profilearrangement that allows positioning of support members 107, 127 in thedisc space 220, even if the disc space has collapsed due to removal ofdistraction. Abutment members 104, 124 are positioned in contact withthe adjacent vertebral bodies, preventing over insertion of guidemembers 100, 120 into the disc space. In the illustrated embodiment,abutment members 104, 124 are orthogonally oriented to the central axisof the guide members, aligning guide members 100, 120 for implantinsertion approach along or parallel to, for example, the saggital orcoronal planes in spinal procedures. In another embodiment, abutmentmembers are obliquely oriented to the central longitudinal axis of guidemembers 104, 124 to facilitate placement of guide members 100, 120 in anapproach obliquely oriented to, for example, the sagittal and coronalplanes in spinal procedures.

In FIG. 16 implant 160 is advanced distally between guide members 100,120 by rotating drive member 40 within housing 22, distally advancingdrive member 40 and thus spreader 60 and implant 160 along guide members100, 120. As the implant 160 and spreader 60 are advanced, the guidemembers 100, 120 are spread apart or separated from one another. Thisseparation causes support members 107, 127 to exert a distraction forceon the vertebral endplates, separating vertebrae 220, 222 a sufficientdistance to accommodate implant 160 therebetween.

In FIG. 17 implant 160 is positioned in the spinal disc space 224. Wings64, 66 are aligned with abutment members 104, 124 adjacent the vertebralbodies 220, 222, respectively. Support members 107, 127 however, arepositioned between the inserted implant 160 and the adjacent vertebralendplate, making withdrawal of inserter 20 from the disc spacedifficult. Wings 64, 66 each include a distal end wall that tapersproximally along the respective body 65, 67 to the enlarged outer end ofthe respective wing 64, 66. This allows wings 64, 66 to better conformto the anatomy of vertebrae 220, 222 at the transition between theendplates and the outer surfaces of the vertebral bodies, and preventsthe wings 64, 66 from contacting the vertebral bodies before implant 160is positioned at the desired location in the disc space 224.

Slots 102, 122 extend through abutment members 104, 124, providing anavenue for further advancement of spreader 60 relative to guide members100, 120. In FIG. 18, drive member 40 has been rotated to completelydisplace spreader 60 to the distal ends of slots 102, 122. Since wings64, 66 contact the adjacent vertebrae 220, 222, spreader 60 cannotadvance toward the disc space. Thus, wings 64, 66 act on vertebralbodies 220, 222 to displace guide members 100, 120 proximally,withdrawing support members 107, 227 from the space between implant 160and the adjacent vertebral endplates. This allows inserter instrument 20to be readily withdrawn from the operative site without twisting orimpaction, which could disrupt implant positioning in the disc space.

As implant 160 is guided between guide members 100, 120 into the spacebetween the adjacent bony portions, the positioning of implant 160 iscontrolled in the cephalad/caudal directions by contact of guidesurfaces 101, 121 with implant 160. Guide surfaces 101, 121 alignimplant 160 with the space between the adjacent bony portions. Thelateral positioning of implant 160 along guide members 100, 120 iscontrolled by engagement of implant holder 140 with implant 160 so thatimplant 160 does not slip out from between guide members 100, 120, whereit might contact or damage tissue, nerves, vasculature or other tissuestructures adjacent the bony portions on the approach to the spacetherebetween. Wings 64, 66 of spreader 60 extend through slots in theupper and lower guide members, and are centrally located to minimizeintrusion into the surrounding tissue. The spreader and guide memberarrangement further facilitates rapid loading and unloading of animplant between the guide members.

The instruments discussed herein can protect the adjacent tissue andvasculature from the implant during insertion by preventing the implant160 and spreader 60 from twisting and moving outside the guide pathduring insertion. The instruments further protect the bony structuresbetween which the implant is inserted during insertion, and facilitatewithdrawal of the implant after it is positioned in the space betweenthe bony structures. Furthermore, the instruments can be adapted toguide insertion of implants of various heights and various taper angles,and to provide varying spacing between adjacent bony portions customizedto fit the particular implant. The instruments include a low profile inthe operative space, facilitating visualization and placement ofadditional instruments in the operative approach to the bony structures.The instruments are simple to disassemble, allowing for cleaning and useof selected guide members from a set of guide members, providingconvenience and flexibility to the surgeon during the surgicalprocedure.

The implants discussed herein can be fusion implants adapted to permitfusion of the adjacent bony portions. Such fusion implants can be packedwith bone growth promoting material and/or therapeutic agents. Theimplants discussed herein can also be any spinal implant movable betweenguide members 100, 120, such as interbody spacers, artificial disccomponents or devices, or other implants desired to be positionedbetween adjacent bony portions.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character. All changes andmodifications that come within the spirit of the invention are desiredto be protected.

1-40. (canceled)
 41. A system, comprising: a spinal implant positionablein a space between adjacent bony portions; a surgical instrument fordelivering said spinal implant to the space, said surgical instrumentincluding: a housing; a pair of opposing guide members extendingdistally from said housing, said pair of guide members each including anelongated body with an outer surface and an opposite inner surfacefacing the inner surface of the other guide member with said spinalimplant being positionable between said inner surfaces, at least one ofsaid guide members further including a distally extending elongated slotextending between and opening through said inner surface and said outersurface of said at least one guide member; a central body between saidpair of guide members, said central body including at least one wingextending therefrom slidingly received in said slot of said at least oneguide member; and a drive member extending from said central body thatis operable to distally advance said central body and said spinalimplant between said guide members.
 42. The system of claim 41, whereinsaid housing includes a coupling portion and a drive member engagingportion extending proximally from said coupling portion, said drivemember engaging portion and said coupling portion including a passageextending therethrough for receiving said drive member.
 43. The systemof claim 41, wherein said drive member includes a shaft threadinglyengaged in a passage of said housing and a handle at a proximal end ofsaid shaft.
 44. The system of claim 43, further comprising an implantholder extending through said drive member and said central body, saidimplant holder including an adjustment knob at a proximal end thereofand a distal end extending distally of said central body for engagementwith said spinal implant.
 45. The system of claim 41, wherein said pairof guide members each include an abutment member adjacent said distalend thereof, said abutment member projecting from said outer surface ofsaid respective guide member.
 46. The system of claim 45, wherein saidabutment members are each orthogonally oriented relative to a centralaxis of said respective guide member.
 47. The system of claim 45,wherein said slot extends through said abutment member of said at leastone guide member.
 48. The system of claim 45, wherein each of said guidemembers includes a support member extending distally of said abutmentmember thereof, said support members being positionable in the spacebetween the adjacent bony portion with said abutment members in contactwith respective ones of the adjacent bony portions.
 49. The system ofclaim 41, wherein: said housing comprises a coupling portion including apair of upper fingers each defining a proximally opening receptacle anda pair of lower fingers each defining a proximally opening receptacle;and each of said guide members includes a proximal end adapted to bepositioned between a corresponding pair of said upper and lower fingers,said guide members each further including a crossbar rotatably andremovably received in said receptacles defined by said correspondingpair of fingers.
 50. The system of claim 41, wherein said at least onewing includes a body extending from said central body and an enlargedouter end, said enlarged outer end being sized to capture said wing insaid slot of said at least one guide member in which said wing isreceived.
 51. The system of claim 50, wherein said slot includes anenlarged proximal end opening adapted to permit passage of said enlargedouter end of said wing therethrough.
 52. The system of claim 41, whereinsaid inner surfaces are planar.
 53. The system of claim 41, wherein saidslot includes a distal end located proximally of a distal end of said atleast one guide member.
 54. The system of claim 41, further comprising adistractor including a distractor head extending from a distal end of ashaft, said distractor head including a height extending between upperand lower surfaces of said distractor head to separate the adjacent bonyportions to a desired disc space height when said distractor head ispositioned between said adjacent bony portions.
 55. The system of claim54, further comprising a rasp head, wherein said distractor head andsaid rasp head are each removably engageable with said distal end ofsaid shaft.
 56. The system of claim 41, wherein said spinal implantincludes bone growth material.
 57. A system comprising: a spinal implantpositionable in a space between adjacent bony portions; an inserterinstrument including: a housing; pair of opposing guide membersextending distally from said housing, said pair of guide members eachincluding an elongate body with an outer surface and an opposite innersurface facing the inner surface of the other guide member, at least onesaid guide members including an elongated slot extending between andopening through said inner surface and said outer surface thereof withsaid spinal implant being positionable between said inner surfaces, saidat least one guide member further including an abutment member adjacenta distal end of said at least one guide member with said slot of said atleast one guide member extending through said abutment member, saidabutment member being positionable in contact with at least one of theadjacent bony portions; a central body between said pair of guidemembers, said central body including at least one wing extendingtherefrom slidingly received in said slot of said at least one guidemember; and drive member extending proximally from said central bodythrough said housing, said drive member being operable to advance saidcentral body and said spinal implant distally between said guidemembers.
 58. The system of claim 57, wherein said slot of said at leastone guide member includes a distal end between said abutment member andsaid distal end of said at least one guide member.
 59. A systemcomprising: a spinal implant positionable in a space between adjacentbony portions; an inserter instrument including: a housing; a pair ofopposing guide members coupled to said housing, each of said pair ofguide members including a body with an outer surface and an oppositeguide surface, wherein said guide surfaces face one another and at leastone of said guide members includes an elongated slot extending throughsaid outer surface and said guide surface thereof, said spinal implantbeing positionable between said guide surfaces of said guide members; aspreader positioned between said pair of guide members, said spreaderincluding a central body and at least one wing extending therefrom, saidat least one wing being slidingly received in said at least one slot ofsaid at least one guide member; and a drive member coupled to saidspreader and operable to forwardly advance said spreader and said spinalimplant positioned forwardly of said spreader toward distal ends of saidguide members, wherein said at least one wing includes a body extendingfrom said central body and an enlarged outer end, said enlarged outerend being sized to capture said wing in said slot of said at least oneguide member.
 60. The instrument of claim 59, wherein said guidesurfaces are planar and said at least one slot includes an enlargedproximal end opening adapted to permit passage of said enlarged outerend of said wing therethrough.